Film compositions are often utilized with many substrates to provide beneficial characteristics and/or properties to the substrate. As one example, conventional fog resistant films may be applied to glass or mirrored surfaces to prevent the formation of water droplets thereon.
Many conventional fog resistant films comprise multiple laminated layers, e.g., a polycarbonate or polyester layer with a polyurethane or silane coating. These layers may be formulated so that the layers adhere to one another. In use, however, these layers may separate from one another, creating performance and/or durability problems.
Other conventional fog resistant films utilize a one-piece configuration. These fog resistant films are thin and may comprise a cellulose ester portion and a fog resistant region. The fog resistant film may be formed by treating a cellulose acetate film with an alkali solution and drawing/stretching the film to impart properties therein. Japanese Patent Application No. 2013099879A and International Publication No. 2008/029801A1, both of which are incorporated herein by reference, disclose such fog resistant films and methods for preparing such films. These fog resistant films, however, may suffer from insufficient fog resistance and/or a lack of film transparency, e.g., haziness. Also, these fog resistant films are processed to be very thin in thickness. These references teach that if the films are made to be thicker, the resultant films may form wrinkles or the outer layer may peel off due to the substantial dimensional change when moisture is absorbed. Also, the fog-resistant films may not have the performance characteristics, e.g., toughness and/or durability, necessary for many (anti-fog) applications. In addition, these films may require particular processing steps that make production difficult.
The need exists for an anti-fog composition having substantial thickness and durability as well as improved anti-fogging characteristics and/or improved clarity, e.g., reduced haziness.